A team of engineers from Rutgers University–New Brunswick has created a human-like 3D-printed smart gel that can walk underwater as well as grab and move objects.
This new technology could lead to the development of soft robots that can mimic an octopus’s ability to walk underwater and bump into things without causing damage.
In addition, the smart gel could be used for creating artificial muscle in the heart and stomach, as well as for diagnosing disease, detecting and delivering drugs, and performing underwater inspections.
The study is published online in ACS Applied Materials & Interfaces.
How does it work?
The researchers developed a system to 3D-print electroactive hydrogels, a solid material made of around 70 percent water that can change and move shape when activated by electricity.
During the printing process, the researchers project light onto a light-sensitive solution that becomes a gel. Then, they place the gel in an electrolyte, or salty water solution, and apply electricity to it through two thin wires.
The electricity triggers motion such as walking forward, walking backward, and grabbing and moving objects, while the speed is controlled by changing its dimensions. For example, thin is faster than thick.
In addition, the gel can bend or change shape depending on the strength of the electrolyte solution and electric field.
“This study demonstrates how our 3D-printing technique can expand the design, size and versatility of this smart gel,” Howon Lee, an assistant professor in the Department of Mechanical and Aerospace Engineering (MAE) and senior author of the study, said in a statement.
“Our microscale 3D-printing technique allowed us to create unprecedented motions.”
Future applications
Soft materials like the hydrogel are typically flexible, cheaper to manufacture than hard materials, and have the potential to be miniaturized.
Until now though, previous research on hydrogels has been limited due to its two-dimensionality.
The Rutger team’s ability to 3D-print hydrogen has opened the door to greater possibilities.
“Since our 3D printing technique provides the ability to create complex 3D structures, we can achieve more complex and diverse actuations,” said Daehoon Han, a Rutgers MAE doctoral student and lead author of the study.
“In addition, we can precisely control the thickness of the actuator with our 3D printing system, which allows us to control the actuation speed.”
Currently, the largest size 3D-printed hydrogel that the researchers have created is two centimeters tall and one centimeter wide.
The researchers believe they will be able to modify the size and shape of the structure for a number of applications, including biomedical engineering and the creation of soft robots.
“Our 3D printing technique and knowledge of the gel will allow us to create and control various types of gel actuators that are difficult to fabricate with traditional two-dimensional (2D) fabrication methods,” said Han.
“In addition, the gel resembles human tissues that also contain lots of water and are very soft. Therefore, the gel actuators fabricated by our technique could be widely used in various fields, including soft robotics and biomedical applications.”
